reroute_email.module in Reroute Email 7

Intercepts all outgoing emails to be rerouted to a configurable destination.

File

reroute_email.module

<?php

/**
 * @file
 * Intercepts all outgoing emails to be rerouted to a configurable destination.
 */
define('REROUTE_EMAIL_ENABLE', 'reroute_email_enable');
define('REROUTE_EMAIL_ADDRESS', 'reroute_email_address');
define('REROUTE_EMAIL_WHITELIST', 'reroute_email_whitelist');
define('REROUTE_EMAIL_ENABLE_MESSAGE', 'reroute_email_enable_message');
define('REROUTE_EMAIL_ENABLE_DSM', 'reroute_email_enable_dsm');
define('REROUTE_EMAIL_MAIL_KEYS', 'reroute_email_mail_keys');
define('REROUTE_EMAIL_ADDRESS_EMPTY_PLACEHOLDER', '[No reroute email address configured]');

/**
 * Implements hook_module_implements_alter().
 *
 * Ensure reroute_email runs last when hook_mail_alter is invoked.
 */
function reroute_email_module_implements_alter(&$implementations, $hook) {

  // Testing with isset is only necessary if module doesn't implement the hook.
  if ($hook == 'mail_alter') {

    // Move our hook implementation to the bottom.
    $group = $implementations['reroute_email'];
    unset($implementations['reroute_email']);
    $implementations['reroute_email'] = $group;

    // If the queue_mail module is installed, ensure that comes after ours so
    // queued emails are still rerouted.
    if (isset($implementations['queue_mail'])) {
      $group = $implementations['queue_mail'];
      unset($implementations['queue_mail']);
      $implementations['queue_mail'] = $group;
    }
  }
}

/**
 * Implements hook_permission().
 */
function reroute_email_permission() {
  return array(
    'administer reroute email' => array(
      'title' => t('Administer Reroute Email'),
      'description' => t('Administer the Reroute Email module.'),
      'restrict access' => TRUE,
    ),
  );
}

/**
 * Implements hook_menu().
 */
function reroute_email_menu() {
  $items['admin/config/development/reroute_email'] = array(
    'title' => 'Reroute Email',
    'description' => 'Reroute emails to a test address.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array(
      'reroute_email_settings',
    ),
    'access arguments' => array(
      'administer reroute email',
    ),
    'file' => 'reroute_email.admin.inc',
  );
  $items['admin/config/development/reroute_email/settings'] = array(
    'title' => 'Settings',
    'type' => MENU_DEFAULT_LOCAL_TASK,
    'weight' => -10,
  );
  $items['admin/config/development/reroute_email/test'] = array(
    'title' => 'Test email form',
    'type' => MENU_LOCAL_TASK,
    'description' => 'Form for sending test email.',
    'page callback' => 'drupal_get_form',
    'page arguments' => array(
      'reroute_email_test_email_form',
    ),
    'access arguments' => array(
      'administer reroute email',
    ),
    'file' => 'reroute_email.admin.inc',
  );
  return $items;
}

/**
 * Implements hook_mail_alter().
 *
 * This hook is required to change the destination of outgoing emails.
 */
function reroute_email_mail_alter(&$message) {
  global $base_url;
  if (empty($message) || !is_array($message)) {
    return;
  }

  // Allow other modules to decide whether the email should be rerouted by
  // specify a special header 'X-Rerouted-Force' to TRUE or FALSE. Any module
  // can add this header to any own emails in hook_mail or any other emails in
  // hook_mail_alter() implementations.
  if (!empty($message['headers']) && isset($message['headers']['X-Rerouted-Force'])) {
    if (FALSE === (bool) $message['headers']['X-Rerouted-Force']) {
      return;
    }

    // We ignore all module settings if X-Rerouted-Force header was set to TRUE.
  }
  elseif (reroute_email_check($message) === FALSE) {
    return;
  }
  $mailkey = isset($message['id']) ? $message['id'] : t('[mail id] is missing');
  $to = isset($message['to']) ? $message['to'] : t('[to] is missing');
  $message['headers']['X-Rerouted-Mail-Key'] = $mailkey;
  $message['headers']['X-Rerouted-Website'] = $base_url;

  // Unset Bcc and Cc fields to prevent emails from going to those addresses.
  if (isset($message['headers']) && is_array($message['headers'])) {

    // Ensure we catch all Cc and Bcc headers, regardless of case,
    // and protecting against multiple instances of the "same" header.
    $header_keys = array();
    foreach (array_keys($message['headers']) as $key) {
      $header_keys[strtolower($key)][] = $key;
    }
    if (!empty($header_keys['cc'])) {
      foreach ($header_keys['cc'] as $header) {
        $message['headers']['X-Rerouted-Original-Cc'] = $message['headers'][$header];
        unset($message['headers'][$header]);
      }
    }
    if (!empty($header_keys['bcc'])) {
      foreach ($header_keys['bcc'] as $header) {
        $message['headers']['X-Rerouted-Original-Bcc'] = $message['headers'][$header];
        unset($message['headers'][$header]);
      }
    }
  }

  // Get reroute_email_address, or use system.site.mail if not set.
  $rerouting_addresses = variable_get(REROUTE_EMAIL_ADDRESS, variable_get('site_mail', ini_get('sendmail_from')));
  $message['headers']['X-Rerouted-Original-To'] = $to;
  $message['to'] = empty($rerouting_addresses) ? REROUTE_EMAIL_ADDRESS_EMPTY_PLACEHOLDER : $rerouting_addresses;

  // Format a message to show at the top.
  if (variable_get(REROUTE_EMAIL_ENABLE_MESSAGE, 1)) {
    $message_lines = array(
      t('This email was rerouted.'),
      t('Web site: @site', array(
        '@site' => $base_url,
      )),
      t('Mail key: @key', array(
        '@key' => $mailkey,
      )),
      t('Originally to: @to', array(
        '@to' => $to,
      )),
    );

    // Add Cc/Bcc values to the message only if they are set.
    if (!empty($message['headers']['X-Rerouted-Original-Cc'])) {
      $message_lines[] = t('Originally cc: @cc', array(
        '@cc' => $message['headers']['X-Rerouted-Original-Cc'],
      ));
    }
    if (!empty($message['headers']['X-Rerouted-Original-Bcc'])) {
      $message_lines[] = t('Originally bcc: @bcc', array(
        '@bcc' => $message['headers']['X-Rerouted-Original-Bcc'],
      ));
    }

    // Simple separator between reroute and original messages.
    $message_lines[] = '-----------------------';
    $message_lines[] = '';
    $msg = implode(PHP_EOL, $message_lines);

    // Prepend explanation message to the body of the email. This must be
    // handled differently depending on whether the body came in as a
    // string or an array. If it came in as a string (despite the fact it
    // should be an array) we'll respect that and leave it as a string.
    if (is_string($message['body'])) {
      $message['body'] = $msg . $message['body'];
    }
    else {
      array_unshift($message['body'], $msg);
    }
  }

  // Abort sending of the email if the no rerouting addresses provided.
  if ($rerouting_addresses === '') {
    $message['send'] = FALSE;

    // Extensive params keys cause OOM error in var_export().
    unset($message['params']);

    // Record a variable dump of the email in the recent log entries.
    $message_string = var_export($message, TRUE);

    // Record a variable dump of the email in the recent log entries.
    watchdog('reroute_email', 'Aborted email sending for <em>@message_id</em>.<br />Detailed email data: Array $message <pre>@message</pre>', array(
      '@message_id' => $message['id'],
      '@message' => $message_string,
    ));

    // Let users know email has been aborted, but logged.
    if (variable_get(REROUTE_EMAIL_ENABLE_DSM, 1)) {
      drupal_set_message(t('<em>@message_id</em> was aborted by reroute email; site administrators can check the recent log entries for complete details on the rerouted email.', array(
        '@message_id' => $message['id'],
      )));
    }
  }
  elseif (variable_get(REROUTE_EMAIL_ENABLE_DSM, 1)) {

    // Display a Drupal status message to let users know email was rerouted.
    drupal_set_message(t('Submitted email, with ID: <em>@message_id</em>, was rerouted to configured address: <em>@reroute_target</em>. For more details please refer to Reroute Email settings.', array(
      '@message_id' => $message['id'],
      '@reroute_target' => $message['to'],
    )));
  }
}

/**
 * Implements hook_mail().
 */
function reroute_email_mail($key, &$message, $params) {
  if ('reroute_email_test_email_form' !== $message['id']) {
    return;
  }
  $message['headers']['Cc'] = $params['cc'];
  $message['headers']['Bcc'] = $params['bcc'];
  $message['subject'] = $params['subject'];
  $message['body'][] = $params['body'];
}

/**
 * Helper function to determine a need to reroute.
 *
 * @param array $message
 *   A message array, as described in hook_mail_alter().
 *
 * @return bool
 *   Return TRUE if should be rerouted, FALSE otherwise.
 */
function reroute_email_check(array $message) {

  // Disable rerouting according to admin settings.
  if (!variable_get(REROUTE_EMAIL_ENABLE, FALSE)) {
    return FALSE;
  }

  // Check configured mail keys filters.
  $keys = reroute_email_split_string(variable_get(REROUTE_EMAIL_MAIL_KEYS, ''));
  if (!empty($keys) && !(in_array($message['id'], $keys, TRUE) || in_array($message['module'], $keys, TRUE))) {
    $message['header']['X-Reroute-Status'] = 'MAILKEY-IGNORED';
    return FALSE;
  }

  // Split addresses into arrays.
  $original_addresses = reroute_email_split_string($message['to']);
  $whitelisted_addresses = reroute_email_split_string(variable_get(REROUTE_EMAIL_WHITELIST, ''));
  $whitelisted_domains = array();

  // Split whitelisted domains from whitelisted addresses.
  foreach ($whitelisted_addresses as $key => $email) {
    if (preg_match('/^\\*@(.*)$/', $email, $matches)) {

      // The part after the @ sign is the domain and according to RFC 1035,
      // section 3.1: "Name servers and resolvers must compare [domains] in a
      // case-insensitive manner".
      $domain = drupal_strtolower($matches[1]);
      $whitelisted_domains[$domain] = $domain;
      unset($whitelisted_addresses[$key]);
    }
  }

  // Compare original addresses with whitelisted.
  $invalid = 0;
  foreach ($original_addresses as $email) {

    // Check whitelisted emails and domains.
    $domain = drupal_strtolower(drupal_substr(strrchr($email, '@'), 1));
    if (in_array($email, $whitelisted_addresses, TRUE) || in_array($domain, $whitelisted_domains, TRUE)) {
      continue;
    }

    // Just ignore all invalid email addresses.
    if (valid_email_address($email) === FALSE) {
      $invalid++;
      continue;
    }

    // No need to continue if at least one address should be rerouted.
    $message['header']['X-Reroute-Status'] = 'REROUTED';
    return TRUE;
  }

  // Reroute if all addresses are invalid.
  if (count($original_addresses) === $invalid) {
    $message['header']['X-Reroute-Status'] = 'INVALID-ADDRESSES';
    return TRUE;
  }

  // All addresses passes whitelist checks.
  $message['header']['X-Reroute-Status'] = 'WHITELISTED';
  return FALSE;
}

/**
 * Split a string into an array by pre defined allowed delimiters.
 *
 * Items may be separated by any number and combination of:
 * spaces, commas, semicolons, or newlines.
 *
 * @param string $string
 *   A string to be split into an array.
 *
 * @return array
 *   An array of unique values from a string.
 */
function reroute_email_split_string($string) {
  $array = preg_split('/[\\s,;\\n]+/', $string, -1, PREG_SPLIT_NO_EMPTY);

  // Remove duplications.
  $array = array_unique($array);
  return $array;
}

/**
 * Validate multiple email addresses field.
 */
function reroute_email_element_validate_addresses($element, &$form_state, $form) {
  $field_name = $element['#name'];

  // Allow only valid email addresses.
  $addresses = reroute_email_split_string($form_state['values'][$field_name]);
  foreach ($addresses as $address) {
    if (!valid_email_address($address)) {
      form_set_error($field_name, t('@address is not a valid email address.', array(
        '@address' => $address,
      )));
    }
  }

  // Save value in usable way to use as `to` param in drupal_mail.
  // String "[e-mail]; ;; , ,," save just as "[e-mail]".
  // This will be ignored if any validation errors occur.
  form_set_value($form[$field_name], implode(',', $addresses), $form_state);
}

Functions

Name	Description
reroute_email_check	Helper function to determine a need to reroute.
reroute_email_element_validate_addresses	Validate multiple email addresses field.
reroute_email_mail	Implements hook_mail().
reroute_email_mail_alter	Implements hook_mail_alter().
reroute_email_menu	Implements hook_menu().
reroute_email_module_implements_alter	Implements hook_module_implements_alter().
reroute_email_permission	Implements hook_permission().
reroute_email_split_string	Split a string into an array by pre defined allowed delimiters.

Constants

Name	Description
REROUTE_EMAIL_ADDRESS
REROUTE_EMAIL_ADDRESS_EMPTY_PLACEHOLDER
REROUTE_EMAIL_ENABLE	@file Intercepts all outgoing emails to be rerouted to a configurable destination.
REROUTE_EMAIL_ENABLE_DSM
REROUTE_EMAIL_ENABLE_MESSAGE
REROUTE_EMAIL_MAIL_KEYS
REROUTE_EMAIL_WHITELIST